To fashion a work of glass, a glassblower must heat the object, shape it, and then cool it down. Fredberg and his colleagues have shown that the cell modulates its mechanical properties and changes its malleability in much the same way. But instead of changing temperature, the cell changes a temperature-like property that has much the same effect.
Using an array of novel nanotechnologies developed by the researchers at HSPH, Fredberg et al. discovered the basic physical laws that describe cell mechanical behavior. Previously, the classical model of cell mechanical behavior had pictured the cell as a viscous fluid core contained by an elastic cortical membrane, but their findings did not at all conform to that picture. The team's experiments show that the cell is a strange intermediate form of matter that is neither solid nor fluid, but retains features of both. Moreover, as the cell goes about its routine business of stretching, spreading, and contracting, it can vary that temperature-like property and control where it sits along the spectrum between solid-like and fluid-like states.
"These findings have important lessons for understanding the dynamics of structural proteins at a scale that is intermediate between the single molecule and integrative cellular function. This is a collective phenomenon of many molecules interacting in concert, and would disappear
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Contact: Christina Roache
croache@hsph.harvard.edu
617-432-6052
Harvard School of Public Health
20-Jun-2005